Accurately analyzing internal conditions of a furnace is an essential task for an operator to better control temperatures of different regions in a furnace enclosure for producing products more efficiently and saving energy-related costs. Typically, image-capturing devices, such as color cameras, infrared spectrometers, filtered cameras, and the like, are installed in the furnace enclosure for detecting the temperatures of the furnace enclosure. Intensities of image pixels received from the devices have a direct relationship with the temperatures of viewed surfaces inside the furnace. Similarly, multi-spectral cameras have been used to detect the temperature of a flame and gas species.
A certain method of video-based technology provides color or intensity images to the operator allowing the operator to manually interpret the state of the combustion process based on the images. An exemplary intensity-temperature calibration and transformation are disclosed in commonly assigned U.S. patent application Ser. No. 14/306,063, which is incorporated by reference in its entirety. Another technology performs off-line intensity-temperature calibration and maps each color image to a specific temperature image, thereby providing a two-dimensional (2D) projection of the temperature and/or radiance field. Other technologies, such as laser, and acoustic, offer three-dimensional (3D) temperature and/or radiance field estimation at specific locations inside the furnace enclosure. However, a number of required sensors, a related cost, and a complicated installation often make such systems impractical in a large scale enclosure. An exemplary 3D temperature and/or radiance field estimation system and method are disclosed in commonly assigned U.S. patent application Ser. No. 14/296,265, and U.S. patent application Ser. No. 14/296,286, which are incorporated by reference in their entirety.
The 3D visualization of the operation inside the furnace enclosure in a refining and petrochemical industry has been a difficult task. Conventionally, small viewports on a side of the furnace are used by furnace operators to look inside the furnace for a visual assessment of the operation. Each viewport typically provides a limited field of view, and thus some internal regions of the furnace are not clearly visible from the side viewport.
Moreover, temperatures of the internal regions of the furnace are extremely high adjacent the viewports, and thus it may be undesirable to stand close to the viewports for the operators. In certain cases, the operators commonly experience heat exhaustion and minor skin burns while standing near the viewports for visual assessment of the combustion process. Due to this exceptionally uncomfortable and undesirable experience of being close to the viewports, the operators often make a hasty interpretation of what has been viewed through the viewports, thereby causing inaccurate assessment of the combustion process.
Another technology for video-based, three-dimensional temperature and/or radiance field estimation applies thermal radiation transfer equations to the temperature images. However, this method is inefficient and inaccurate, and does not provide a required resolution and accuracy due to complex, iterative computations required to resolve unknown temperature and radiance fields in the enclosure. Another reason for the inaccuracy is attributed to poor-quality images caused by incorrect or limited controls of the image-capturing devices. Achieving an acceptable accuracy in high resolution and accurate alignment of the images along with information about a physical structure of the enclosure is essential. Further, relative positions of the image-capturing devices and imaging areas, such as enclosure walls, often shift their alignments and thus cause significant errors.
Therefore, there is a need for an improved method of analyzing conditions of the combustion process in the enclosure without generating substantial errors or variations during operation. Further, the accurate analysis of the furnace conditions provides the operator a better tool to improve the efficiency of the furnace enclosure.